Diesel Engine Motor Oil Performance Comparison

Introduction

• Diesel engines are expensive, so selecting an effective motor oil is crucial for protection and longevity.
• Objective: Test and compare six different brands of SAE 15W-40 diesel engine motor oils.

Test Criteria

• Cold flow performance at -40° C (-40° F).
• Protection against engine wear.
• Resistance to thermal breakdown and evaporation.
• Oil film strength (lubricity).

Test Setup

1. Shake oil containers to mix additives and label samples to avoid mix-ups.
2. High-temperature viscosity measured around 70°F as an indicator of flow in a warmed-up engine.

Cold Flow Test at 70°F

• Competitors: Mobile Delvac, Rotella T6, Royal Purple, Schaefer's, Hot Shots, AMS Oil
• Results:
  • Royal Purple: 2.98 seconds
  • Mobile Delvac: 3.03 seconds
  • Rotella T6: 3.08 seconds
  • Schaefer's: 3.13 seconds
  • Hot Shots: 2.46 seconds (fastest)
  • AMS Oil: Slower than Hot Shots

Evaporation and Thermal Breakdown Test

• Expose oil samples to 400°F for two hours
• Measure evaporative loss:
  • Mobile Delvac: 6.64g
  • Rotella T6: 6.64g
  • Royal Purple: 5.25g (least evaporative loss)
  • Schaefer's: 6.23g
  • Hot Shots: 5.52g
  • AMS Oil: 4.14g (least evaporative loss)

Lubricity Test (Oil Film Strength)

• Pour 40mL heated oil into test cups and pre-coat test wheel and pin to avoid dry start.
• Measure wear scar on test pins:
  • Mobile Delvac: 5.94mm scar
  • Rotella T6: 5.63mm scar
  • Royal Purple: 5.6mm scar
  • Schaefer's: 5.27mm scar (best performance)
  • Hot Shots: 5.51mm scar
  • AMS Oil: 5.22mm scar (best performance)

Cold Flow Test at -40° C (-40° F)

• Competitors: Same as above
• Results:
  • Hot Shots: 95.4 seconds (best)
  • Rotella T6: 134.2 seconds
  • Royal Purple: Second place
  • Schaefer's: Third place
  • AMS Oil: Slowest

Post-Heat Exposure Cold Flow Test

• Results after heat exposure and 24-hour re-freeze:
  • Hot Shots: 108 seconds (still best)
  • Rotella T6: 142 seconds
  • Schaefer's: Second place
  • Royal Purple: Third place
  • Mobile Delvac: Slowest

Additive Content Evaluation

• Focus on anti-wear additives (parts per million, ppm):
  • AMS Oil: 248 ppm (highest)
  • Schaefer's: 242 ppm
  • Royal Purple: 2,129 ppm
  • Mobile Delvac: 1,451 ppm (lowest)

Conclusion and Recommendations

• Mobile Delvac: Most affordable but has the lowest anti-wear additives.
• Rotella T6: Good overall performance and value; moderate additive content.
• Royal Purple: Good evaporation resistance; performs well in cold but not post-heat.
• Schaefer's: Robust additive package, good overall performance.
• Hot Shots: Excellent cold flow performance, even post-heat; moderate additive content.
• AMS Oil: Best anti-wear additive package, but most expensive.
• Each oil has unique strengths; best choice depends on specific requirements.

Viewer Engagement

• Invitation to viewers to suggest future testing ideas.